Roofing Assembly Simulated Heat and Light Test

The goal of this project is to search for a testing procedure for roof covering products that will radiate both heat and light onto a roof covering and then measure the impact that a given roof covering product has on heat transfer through the entire roofing assembly. Identical roof assemblies were built with ethylene propylene diene terpolymer (EPDM) rubber roof membrane over a wood deck. Sixteen heat lamps were positioned 1.14 m [45 in.] above the roof covering product to provide both heat and light. Thermocouples were placed on the underside of the wood deck and were insulated from outside air. The roofing assembly and the roof covering temperatures were brought to 18°C to 21°C prior to testing. Heat and light were radiated onto the roof coverings for 360 min and the under deck temperature was recorded at 1 min intervals for 600 min. Tested roof coverings included gravel, growing media, coatings, and panels in the form of concrete, ceramic foam, and rubber. The results of the tests have shown data similar to that which were recorded during warm, sunny days. As expected, the highest temperatures were achieved by the uncovered and uncoated black EPDM roof assembly. The temperature of this assembly diminished almost immediately upon the removal of the heat and light source. Thicker layers of growing media and ceramic foam block did not reach the peak temperature until several hours after the heat lamps were turned off. The roof assembly covered with reflective coating showed realistic resistance to the heat and light source. This is a significant advancement in the effort to provide equitable data for all roof coverings. The test provides a standard method of collecting data for traditional roof coverings as well as emerging technology roof covering materials to evaluate a roofing assemblies’ thermal performance from solar heat gain.